Slightly baffled SLX 12speed on Sunrace Cassette issue

[DR ◣◢]

This one has me a little stumped. 

 

Running the new SLX 12spd with a Sunrace 12spd cassette and KMC chain. 

 

On the stand the shifting is perfectly acceptable. Obviously slower than the XTR I'm used to. 
On the trail everything was fine across the whole cassette for the first 2 rides. Ride number 3 had some noise when putting power on the top 3 gears (towards the 51). On ride 4 is was really noisy and I ended up not using them. 

 

Now back on the stand and everything is fine again. I did notice that there is a slight bit of tension on the chain when shifting into these gears. Maybe because there is no load on the chain? 

 

What I've done so far. 

 

- B Tension is 100% correct lining up the teeth on the cassette with the line on the derailleur cage

- Low and high is 100% 

- Cable isn't pinched off anywhere. 

- Performed the standard gear setting after the initial few rides. 

 

Maybe I missed something here. Advice would be greatly appreciated. 

[BaGearA]

There might be a tight link, this assumes that the chain was joined somewhere by someone that didn't ease the plates off each other

[DR ◣◢]

Chain is joined with a master link. No tight links anywhere.

 

Wouldn't a stiff link cause shifting issues across the whole cassette?

[Barry]

I have found this issue with GX and Sunrace 12x the B screw setting was the problem and what now is running 100% is way off when using the GX alignment tool so sort of a custom thumbsuck seting but it woeks

[DR ◣◢]

So the problem is more likely with the cassette? I’ll go a couple of mm up and down on the adjustment to see if I can smooth it out.

[Barry]

Find that Sunrace on a Shimano free hub has more play or movement than XD that is solid so the movement can also throw a spanner in the works 1mm on the hub can end up 2or3mm on the teeth of a 50T

[DR ◣◢]

Find that Sunrace on a Shimano free hub has more play or movement than XD that is solid so the movement can also throw a spanner in the works 1mm on the hub can end up 2or3mm on the teeth of a 50T

Could explain why the first few rides were ok and now not so much.

[DieselnDust]

When you say noisy what do you mema9?

Slipping noisy

skipping noisy

misaligned noisy tick tick tick noises

[W@nted]

Full suss or hardtail? Is the chain length correct?

[Butterbean]

Are you certain the hanger is straight?

[DR ◣◢]

When you say noisy what do you mema9?

Slipping noisy

skipping noisy

misaligned noisy tick tick tick noises

Crunchy grindy noise.

[DR ◣◢]

Full suss or hardtail? Is the chain length correct?

Full sus. Chain is 100% correct length.

[DR ◣◢]

Are you certain the hanger is straight?

Yes it is.

[Jewbacca]

hmm.... So here is my 2c.....

 

Sometimes when getting into the big gears under load, the chain pulls the rd ever so slightly in towards the frame, so the swing arc is a fraction of a MM closer to the cogs when shifting. 

 

This means that any debris (or just the chain) tends to catch the bigger gear ever so slightly before the derailleur moves 'down' in it's arc.

 

I don't run dish plates on the back of my bikes, but have had to fix many. Crunching usually means that the top jockey wheel needs to be set ever so slightly away from the cassette or the tension needs to be half a barrel turn less.

 

Or both.

 

But without seeing it that is just going on past crunchy noises of my mates with big gears

[Eddie Stafford]

Based on the previous topic about problems with the clutch of 12 spd Shimano derailleurs, why don't you open and lube the clutch and see if that makes a difference.

 

For a quick fix I squirted oily chain lube (Finish Line wet lube) into the clutch and it immediately "fixed" the problem. When I have more time I will clean and grease the clutch properly.    

[DR ◣◢]

Based on the previous topic about problems with the clutch of 12 spd Shimano derailleurs, why don't you open and lube the clutch and see if that makes a difference.

 

For a quick fix I squirted oily chain lube (Finish Line wet lube) into the clutch and it immediately "fixed" the problem. When I have more time I will clean and grease the clutch properly.    

 

Did you have this exact issue and it was a dry clutch issue?